This invention relates to tool holders including chucks, tool adapters and extensions.
Tool holders are in common use in the milling and related machining industries as a means of facilitating attachment of a tool, such as a milling cutter, to a machine, such as a milling machine. Prior art tool holders have been secured to the spindle of the milling or other machine primarily by one of two mounting arrangements. In one mounting arrangement, commonly referred to as a flange mount, the holder is secured to the spindle by a plurality of circumferentially spaced screws passing upwardly through holes in an upper flange of the holder for threaded receipt in tapped bores in the spindle. This arrangement provides a firm, precisely aligned attachment of the holder to the spindle but is subject to fouling of the spindle threads and requires an inordinate amount of time to perform the frequent tool changes that are required in the milling business. In the other mounting arrangement, commonly referred to as a taper mount, the holder includes a frusto-conical upper extension or neck which is pulled upwardly into firm seating engagement with a mating frusto-conical cavity in the spindle by a draw bolt threadably coacting with a threaded central bore in the upper conical extension of the holder. This arrangement provides quick changing of tools but is subject to misalignment or tipping of the tool holder and may require shimming to provide a precisely aligned mount.